The way into the tomb can only be opened if Link plays "Zelda's Lullaby" while standing on the Triforce mark in front of the headstone. Doing this causes the skies to darken and rain to shower down. Eventually, a ball of shining light descends from the skies and shatters the headstone into pieces, allowing Link to enter the passage it once obstructed.

Interestingly, the first chamber of the tomb contain human remains that can be conversed with. They inform Link of the weaknesses of ReDeads, which are encountered further on inside the tomb.